Thermal Spray Coating for Mechanical Face Seals

ABSTRACT

A method of producing a mechanical face seal, the method including a step of obtaining a cast or wrought substrate part having an inner diameter, outer diameter, and a planar surface. The method may include a rough surface treatment step to form pores, peaks, and valleys on the planar surface of the substrate part. The method may further include a spraying step to supply a spray coating material onto the substrate part to form a protective thermal spray coating layer on the substrate part.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is a continuation in part application and claimsthe priority benefit of co-pending U.S. patent application Ser. No.14/482,475, filed Sep. 10, 2014, which is incorporated herein in itsentirety by this reference.

TECHNICAL FIELD

This disclosure relates generally to the field of mechanical componentsformed by a material deposition process, and more particularly to amechanical seal formed using a laser cladding process or a thermal spraycoating process.

BACKGROUND

In equipment and machinery that have rotatable shafts, seals are oftenutilized to retain lubricant while at the same time excluding foreignmatter from bearing surfaces of the rotatable shafts. In particular,metal or mechanical face seals are used in heavy duty rotatingapplications, such as axles, gearboxes, tracked vehicles, conveyersystems, etc., where components are exposed to hostile, abrasive, andcorrosive environments where shaft seals may quickly wear out. Themechanical face seals generally include two identical metal seal ringsthat are mounted face-to-face with one another in two separate housingsor retainers. One of the two metal rings typically remains static withinits respective retainer while the other of the two metal rings typicallyrotates with its counter face.

Due to the operational requirements and the wide range of environmentalconditions in which these components operate in, the metal contactsurfaces of the mechanical face seals may be subject to accelerated wearand tear due to frictional contact, stresses, and temperature extremes,among other things. As a result, the mechanical face seals may be madefrom more durable and exotic materials. However, such materials areexpensive and are difficult to form.

U.S. Patent Application Publication No. 2011/0285091 (the '091Publication), entitled “Method for Applying Wear Resistant Coating toMechanical Face Seal,” purports to address the problem of reducing costwhile maintaining desired corrosion and wear resistant. However, coatingprocesses in related art have suffered from significant failure ofadhesion. Accordingly, there is a need for an improved process forforming mechanical components such as face seals.

SUMMARY

In one aspect, the present disclosure describes a method of producing amechanical face seal. The method may include forming a cast or wroughtsubstrate part, the substrate part having an inner diameter, an outerdiameter, and a planar surface extending between the inner diameter andthe outer diameter. The method may include roughing the planar surfaceof the substrate part. The method may include applying a coatingmaterial onto the planar surface to form a thermal coating layer on thesubstrate part, the coating material comprising at least one of aFe-based alloy, a Ni-based alloy, a Co-based alloy, a carbide-basedmaterial, and a ceramic material.

In another aspect, the present disclosure describes a method ofproducing a mechanical face seal, including forming a cast or wroughtsubstrate part. The substrate part may have an inner diameter, an outerdiameter, and a planar surface extending between the inner diameter andthe outer diameter. The method may include roughing the planar surfaceof the substrate part to form pores, peaks, and valleys on the planarsurface of the substrate part. The method may include spraying a coatingmaterial that has been heated to molten particles, via a heating elementand a spray head, onto the planar surface to form a thermal spraycoating layer on the substrate part, the coating material comprising atleast one of a Fe-based alloy, a Ni-based alloy, a Co-based alloy, acarbide-based material, and a ceramic material.

In yet another aspect, the present disclosure describes a method ofproducing a mechanical face seal, including forming a cast or wroughtsubstrate part, the substrate part having an inner diameter, an outerdiameter, and a planar surface extending between the inner diameter andthe outer diameter. The method may include roughing the planar surfaceof the substrate part. The method may include spraying a coatingmaterial via a sprayer onto the planar surface to form a thermal spraycoating layer on the substrate part, the coating material comprising atleast one of a Fe-based alloy, a Ni-based alloy, a Co-based alloy, acarbide-based material, and a ceramic material. The Fe-based alloy mayconsist of 0.78% to 1.05% carbon, 0.15% to 0.40% manganese, 0.20% to0.45% silicon, 2.0% to 4.5% chromium, 4.5% to 5.5% molybdenum, 5.5% to6.75% tungsten, 1.75% to 2.20% vanadium, up to 0.3% nickel, up to 0.25%copper, up to 0.03% phosphorus, up to 0.03% sulfur, and a balance ofiron. The Ni-based alloy may consist of 16-17% chromium, 3.3% boron,3.8% silicon, 0.8% to 1.0% carbon, and a balance of nickel. The Co-basedalloy may consist of 26.5% to 33% chromium, 0.8% to 2.7% carbon, 3.5% to20% tungsten, 0.8% to 1.2% silicon, up to 3% iron, up to 1.5%molybdenum, up to 1% manganese, and a balance of cobalt. Thecarbide-based material may include at least one of tungsten andchromium. The ceramic material may include at least one of aluminumoxides, cobalt oxides, and titanium oxides.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will become more fully understood from the followingdetailed description, taken in conjunction with the accompanyingfigures, wherein like reference numerals refer to like elements.

FIG. 1 is a perspective view of an exemplary machine in which thedisclosed mechanical face seals may be used, the machine is depictednext to a full-sized sports utility vehicle.

FIG. 2 is a cutaway perspective view of a gearbox used in the exemplarymachine of FIG. 1.

FIG. 3 is a cross-sectional view of a first seal assembly of the gearboxof FIG. 2.

FIG. 4 is a cross-sectional view of a second seal assembly of thegearbox of FIG. 2.

FIG. 5 is a cross-sectional view of an exemplary spring-loaded metalface seal.

FIG. 6 is a flow chart of steps for laser cladding a substrate part toform laser cladded mechanical face seals in accordance with an aspect ofthe disclosure.

FIG. 7 is a partial cross-sectional view of an exemplary substrate partbeing formed in accordance with an aspect of the disclosure.

FIG. 8 is a partial cross-sectional view of the exemplary substrate partof FIG. 7 after exposing a laser to a planar surface of the substratepart and supplying a coating material to the planar surface inaccordance with an aspect of the disclosure.

FIG. 9 is a partial cross-sectional view of the substrate part in FIG. 8depicting a section of a coating surface that may be removed during afinishing process.

FIG. 10 is a partial cross-sectional view of the substrate part in FIG.8 depicting an inner diameter side and an outer diameter side that maybe removed during a finishing process.

FIG. 11 is a flow chart of steps for thermal spray coating a substratepart to form thermally spray coated mechanical face seals in accordancewith an aspect of the disclosure.

FIG. 12 is a partial cross-sectional view of an exemplary substrate partbeing formed in accordance with an aspect of the disclosure.

FIG. 13 is a partial cross-sectional view of the exemplary substratepart of FIG. 12 after supplying a thermal spray coating to a planarsurface of the substrate part in accordance with an aspect of thedisclosure.

FIG. 14 is a partial cross-sectional view of the substrate part in FIG.13 depicting a section of a thermal spray coating surface that may beremoved during a finishing process.

DETAILED DESCRIPTION

Now referring to the drawings, FIG. 1 shows an exemplary machine 10 inrelated art where mechanical face seals may be used to provide a dynamicseal. The machine 10 may be in the form of a mining truck and isdepicted next to a full-sized sports utility vehicle 12 to show andcompare a size and scale of the two machines. The machine 10 istypically employed to transport a payload of several hundred tons andoperates in extreme environmental conditions. The environmental andpayload demands exceed typical demands placed on machinery in otherfields and therefore components must be designed and built to withstandthe extreme conditions and demands.

The machine 10 may be driven by an internal combustion engine (notshown) or other suitable power plant. The engine or suitable power plantmay be activated to provide motive force to rotatably drive a wheel hub11 and associated tires 13 of the machine 10. As shown in FIG. 2, awheel gear unit 14 in the related art may be interposed between theengine of the machine 10 and the wheel hub 11 to provide an appropriateamount of output torque and speed. The wheel gear unit 14 includes aflange 17 that may be used to mount the wheel hub 11.

It should be noted that the machine 10 shown in FIG. 1 and reference toseals is for the purpose of brevity. The material deposition processesof the present disclosure may be utilized with any type of machine andany type of mechanical component in such a machine that may be subjectto operation in extreme environmental conditions. In one non-limitingaspect, the seals produced using the material deposition processes ofthe present disclosure may be used in undercarriage type applications,which may include track rollers, carrier rollers, and idlers.

Referring to FIG. 2, the wheel gear unit 14 may include a firstmechanical face seal assembly 100 and a second mechanical face sealassembly 200. The first mechanical face seal assembly 100 and the secondmechanical face seal assembly 200 provide fluid seals to components ofthe wheel gear unit 14. Leaks or failure at the mechanical face sealassemblies 100, 200 may be detrimental to internal components of thewheel gear unit 14 and may result in accelerated wear and tear,equipment failure, and downtime required for cleaning, repairing, ormaintaining the equipment.

Turning to FIG. 3, the first mechanical face seal assembly 100 mayinclude a fixed retainer 102, a rotating retainer 104, a rotating sealring 110, and a static seal ring 112. An O-ring 108 may be providedbetween the fixed retainer 102 and the static seal ring 112, and betweenthe rotating retainer 104 and rotating seal ring 110. The fixed retainer102 and the rotating retainer 104 may each include angled surfaces tocompress their respective O-rings 108. In response to the compressionforce, the O-rings 108 may press the rotating seal ring 110 and thestatic seal ring 112 against each other such that the rotating seal ring110 applies a frictional torque on the static seal ring 112, therebyforming a fluid seal at interface 106. While a Duo-Cone™ mechanical faceseal is shown in FIGS. 3 and 4 and a spring-loaded metal face sealarrangement is shown in FIG. 5, a laser cladding process or a thermalspray coating process of the present disclosure, as will be described infurther detail below, may be performed on any suitable mechanical faceseal, including but not limited to heavy duty dual face (HDDF) seals.

Turning to FIG. 4, the second mechanical face seal assembly 200 mayinclude a fixed retainer 202, a rotating retainer 204, a static sealring 210, and a rotating seal ring 212. An O-ring 208 may be providedbetween the fixed retainer 202 and the static seal ring 210, and betweenthe rotating retainer 204 and rotating seal ring 212. The fixed retainer202 and the rotating retainer 204 may each include an angled surface tocompress their respective O-rings 208. In response to the compressionforce, the O-rings 208 may press the static seal ring 210 and therotating seal ring 212 against each other such that the rotating sealring 212 applies a frictional torque on the static seal ring 210,thereby forming a fluid seal at interface 206.

The rotating seal ring 110 and the static seal ring 112 together form afirst mechanical face seal 120. The static seal ring 210 and therotating seal ring 212 together form a second mechanical face seal 220.As discussed above, a rotational torque may be applied at the interface106 of the first mechanical face seal 120, via rotation of the rotatingseal ring 110, and at the interface 206 of the second mechanical faceseal 220, via rotation of the rotating seal ring 212, while the wheelgear unit 14 is driven. The seal rings 110, 112, 210, 212 may each bemade of cast iron. However, due to the constant rotational torque andfrictional contact experienced at the interfaces 106, 206, and due tothe extreme operating conditions when utilized in applications such asthe machine 10, the seal rings 110, 112, 210, 212 require regularmaintenance and replacement, leading to prolonged downtime of themachine 10.

Turning to FIG. 5, a spring-loaded metal face seal arrangement 250 isshown. The spring-loaded metal face seal arrangement 250 may be used inthe machine 10 to retain lubricant and/or coolant within components ofthe machine 10 and to prevent intrusion of any debris of foreign matterinto the components of the machine 10. The spring-loaded metal face sealarrangement 250 may be used to provide a seal between a rotatable and astationary structure, or between relatively rotatable structures, suchthat a constant and precise axial sealing force is applied.

The spring-loaded metal face seal arrangement 250 may be installedbetween a first rotatable structure 260 and a second rotatable structure265. The spring-loaded metal face seal arrangement 250 may include afirst seal retainer 252 and a second seal retainer 254, which arerespectively attached to the first rotatable structure 260 and thesecond rotatable structure 265. The spring-loaded metal face sealarrangement 250 may include at least a first seal ring 270, a secondseal ring 280, and a spring member 290. In select aspects, the springmember 290 may include one or more Belleville springs.

The first seal ring 270 may include a first axially facing sealingsurface 272 and a first axially facing recessed surface 274. In selectaspects, the first axially facing sealing surface 272 and the firstaxially facing recessed surface 274 may define a stepped portion.Additionally or alternatively, a sloped ramped portion may extendbetween the first axially facing sealing surface 272 and the firstaxially facing recessed surface 274. In select aspects, the firstaxially facing recessed surface 274 may consist of a sloped portion thatextends laterally from the axially facing sealing surface 272.

The second seal ring 280 may include a second axially facing sealingsurface 282 and a second axially facing recess surface 284. In selectaspects, the second axially facing sealing surface 282 and the secondaxially facing recessed surface 284 may define a stepped portion.Additionally or alternatively, a sloped ramped portion may extendbetween the second axially facing sealing surface 282 and the secondaxially facing recessed surface 284. In select aspects, the secondaxially facing recessed surface 284 may consist of a sloped portion thatextends laterally from the axially facing sealing surface 282.

The first seal ring 270 and the second seal ring 280 may be disposedsuch that the first axially facing surface 272 and the second axiallyfacing surface 282 are opposed face-to-face. The spring member 290 mayprovide an axial force to enable substantially constant engagementbetween the first axially facing surface 272 and the second axiallyfacing surface 282. While the spring member 290 enables substantiallyconstant engagement even as the first axially facing surface 272 and thesecond axially facing surface 282 wear down, the spring-loaded metalface seal arrangement 250 will still require regular maintenance andreplacement due to the extreme operating conditions in which the machine10 is operated.

While efforts have been made to make seal rings out of more exoticmaterials that are more capable of resisting wear, those materials aresubstantially more expensive, and are more difficult and time intensiveto form into the required geometries of the mechanical face seals.Additionally, attempts have been made in the related art to coatmechanical face seals using twin-wire arc (TWA) spray, diamond-likecoatings (DLC), or high velocity oxygen fuel (HVOF). However, priormethods in the related art have led to coatings that lacked durability,delaminated from the substrate, and/or lead to unacceptable surfacecracking or similar failure. Accordingly, there is a need for moredurable and cost effective coating processes.

Referring to FIGS. 6 and 7, the disclosure provides a method of formingmechanical face seals using a laser cladding process that may enable useof less expensive substrates, increase performance, and reducemanufacturing complexity over conventional techniques and/or seal ringsmade of expensive exotic wear resistant substrates such as titanium orzirconium. The method of laser cladding 300 may include an obtainingstep 310 to obtain or form a substrate part 400. In the obtaining step310, the substrate part 400 may be wrought or cast using an SAE 52100alloy steel, SAE 1020 alloy steel, SAE 1040 alloy steel, ductile iron,or grey cast iron. Other materials are contemplated as well. Thesubstrate part 400 may be wrought or cast to have roughly a geometry ofa finished mechanical face seal. In addition, or as an alternative, thesubstrate part 400 may be formed by a powder metallurgy or othersuitable process. In select aspects, the obtaining step 310 may compriserefurbishing, repairing, or salvaging a previously used or damagedsubstrate part in order to obtain the substrate part 400.

After the substrate part 400 has been obtained, the substrate part 400may undergo a preheating step 320. The preheating step 320 may includeheating the substrate part 400 in an oven, applying resistive heating tothe substrate part 400, applying a suitable coil to promote inductionheating of the substrate part 400 and/or a like heating process. Inselect aspects, the suitable coil may be a U-shaped coil or a pancakecoil. In select aspects, a laser 800 may be exposed to a top layer 441of the substrate part 400 to heat at least a planar surface 440 of thesubstrate part 400.

An exposing step 330 may be performed whereby the surface of thesubstrate part 400 is exposed to the laser 800, either for the firsttime, or a subsequent time if a preheating step 320 is performed by thelaser 800. During the exposing step 330, the laser 800 may trace alongthe top layer 441 of the substrate part 400 and at least partially meltthe top layer 441 of material of the substrate part 400.

A supplying step 340 may be performed just before, during, or just afterthe exposing step 330 begins. During the supplying step 340, a coatingmaterial 950 is supplied to the top layer 441 of the substrate part 400at or near a location of the laser 800 being traced on the planarsurface 440, whereby the top layer 441 of the substrate part 400 ismelted together with the coating material 950 via the laser 800 to forman intermediate layer 500. The intermediate layer 500 may include boththe coating material 950 and a material of the substrate part 400, asshown in FIG. 8. The supplying step 340 may further include supplyingthe coating material 950 to be melted by the laser 800 to form acladding layer 600 disposed above the intermediate layer 500, as shownin FIG. 8. In one aspect, the exposing step 330 and/or the supplyingstep 340 may be performed to form the cladding layer 600 without orsubstantially without any cracks or any defects, such as oxides orpores.

A finishing step 350 may be performed on the substrate part 400 toachieve final dimensions required by a particular mechanical face seal.The finishing step 350 may also be performed on the intermediate layer500 and/or the cladding layer 600 formed during the supplying step 340.The finishing step 350 may comprise a surface finishing process whichmay include one or more of grinding, polishing, milling, machining, orother suitable process to finish one or more surfaces of the substratepart 400. The surface finishing process of the finishing step 350 may beperformed to refine one or more of a surface texture, thickness, innerdiameter, outer diameter and/or similar feature of the substrate part400 to obtain final dimensions that correspond to a finished metal faceseal. The finishing step 350 may comprise a heat treatment process,which may be performed before or after the surface finishing process, toenhance material properties of the substrate part 400. The heattreatment process may include thermal hot flattening where the substratepart 400 is compressed in a thermally controlled environment to relieveproduct stresses. In one aspect, the exposing step 330 and/or thesupplying step 340 may be performed to form the cladding layer 600without or substantially without any cracks, and such that cracks do notform in the cladding layer 600 during the finishing step 350.

Referring to FIG. 7, the substrate part 400 may include at least anouter diameter surface 410 and an inner diameter surface 420 extendingalong a common central axis 430. The substrate part 400 may include aplanar surface 440 extending between the outer diameter surface 410 andthe inner diameter surface 420. When processed and finished, the planarsurface 440 of the substrate part 400 may form a surface of a mechanicalseal ring for contact at an interface between two mechanical face seals.As discussed above with respect to the obtaining step 310, the substratepart 400 may be wrought or cast using an SAE 52100 alloy steel, SAE 1020alloy steel, SAE 1040 alloy steel, ductile iron, or grey cast iron. Inselect aspects, the obtaining step 310 may comprise refurbishing,repairing, or salvaging a previously used or damaged substrate part inorder to obtain a substrate part 400.

During the obtaining step 310, the substrate part 400 may be formed intoa ring-shaped element. In select aspects, the substrate part 400 may bemade of SAE 52100 alloy steel, which may have a chemical composition of1.3% to 1.6% chromium, 0.93% to 1.1% carbon, 0.25% to 0.45% manganese,0.15% to 0.35% silicon, up to 0.025% sulfur, up to 0.025% phosphorous,and a balance of iron. In select aspects, the substrate part 400 may bemade of SAE 1020 alloy steel, which may have a chemical composition of0.18% to 0.23% carbon, 0.3% to 0.6% manganese, up to 0.04% phosphorus,up to 0.05% sulfur, and a balance of iron. In select aspects, thesubstrate part 400 may be made of SAE 1040 alloy steel, which may have achemical composition of 0.37% to 0.44% carbon, 0.6% to 0.9% manganese,up to 0.04% phosphorus, up to 0.05% sulfur, and a balance of iron. Inselect aspects, the substrate part 400 may be made of ductile iron,which may have a chemical composition of 3.0% to 3.9% carbon, 1.7% to2.9% silicon, 0.1% to 0.6% manganese, 0.02% to 0.06% magnesium, 0.005%to 0.04% phosphorus, up to 0.04% sulfur, up to 0.4% copper, and abalance of iron. In select aspects, the cast iron substrate may be madeof grey cast iron, which may have a chemical composition of 2.5% to 4.0%carbon, 1% to 3% silicon, and a balance of iron.

During a laser cladding process, the substrate part 400 may bepreheated, as discussed in the preheating step 320 described above. Thesubstrate part 400 may be heated in an oven, resistively heated,inductively heated via a pancake coil or other suitable induction coil,or heated by exposing the top layer 441 of the substrate part 400 to thelaser 800. In select aspects, the laser 800 may trace over the planarsurface 440 to heat up at least the top layer 441 of the planar surface440.

After the substrate part 400 has been obtained, the exposing step 330may be performed, which may occur with or without performance of thepreheating step 320. During the exposing step 330, the laser 800 maytrace along the planar surface 440 of the substrate part 400 causing thetop layer 441 of the planar surface 440 to at least partially melt. Inselect aspects, the exposing step 330 may include adjusting orcontrolling a power level of the laser 800.

Concurrently with or just after the exposing step 330, as the laser 800traces over at least one portion 442 of the top layer 441, the supplyingstep 340 may be performed to supply the coating material 950 to theportion 442 of the planar surface 440 at or near a location of the laser800 traced on the planar surface 440. The supplied coating material 950may be fed through a supplier 900, which is positioned to deliver thecoating material 950 at or near the portion 442 of the planar surface440 being traced by the laser 800. In select aspects, the supplier 900may be attached to a laser generator 850 that generates the laser 800.In select aspects, the supplier 900 may be integral with the lasergenerator 850, as shown in FIG. 7. In select aspects, the supplying step340 may include controlling a feed rate of the coating material 950 viathe supplier 900.

The coating material 950 may be in the form of a wire or a powder, andthe coating material 950 may be made of Fe-based alloys, Ni-basedalloys, and/or Co-based alloys. In select aspects, the coating material950 may include Durmat® 60A, M2 tool steel, Stellite® 1, Stellite® 6, orother suitable material. In select aspects where the coating material950 is supplied in the form of a wire, the wire may be heated prior tobeing supplied to the planar surface 440. In select aspects, the coatingmaterial 950 may consist of a Ni-based alloy having a chemicalcomposition of 16-17% chromium, 3.3% boron, 3.8% silicon, 0.8% to 1.0%carbon, and a balance of nickel. In select aspects, the coating material950 may consist of a Fe-based alloy having a chemical composition of0.78% to 1.05% carbon, 0.15% to 0.40% manganese, 0.20% to 0.45% silicon,2.0% to 4.5% chromium, 4.5% to 5.5% molybdenum, 5.5% to 6.75% tungsten,1.75% to 2.20% vanadium, up to 0.3% nickel, up to 0.25% copper, up to0.03% phosphorus, up to 0.03% sulfur, and a balance of iron. In selectaspects, the coating material 950 may consist of a Co-based alloy havinga composition of 26.5% to 33% chromium, 0.8% to 2.7% carbon, 3.5% to 20%tungsten, 0.8% to 1.2% silicon, up to 3% iron, up to 1.5% molybdenum, upto 1% manganese, and a balance of cobalt.

The supplier 900 may be configured to feed a spool of the wire of thecoating material 950 or to spray a stream of powder of the coatingmaterial 950 to the portion 442 of the planar surface 440. As thecoating material 950 is supplied to the portion 442 of the planarsurface 440, during the supplying step 340, heat from the laser 800and/or the melted top layer 441 of the planar surface 440 may cause thecoating material 950 to melt and mix with the top layer 441 of theplanar surface 440, thereby forming an intermediate layer 500, as shownin FIG. 8. The intermediate layer 500 may include a mix of both thecoating material 950 and the material of the substrate part 400.

The supplying step 340 may further supply coating material 950 to bemelted by the laser 800 and/or heat from the intermediate layer 500 toform a cladding layer 600 disposed above the intermediate layer 500, asshown in FIG. 8. In select aspects, the cladding layer 600 may includeprimarily the coating material 950 or may include exclusively thecoating material 950. In select aspects, a thickness of the intermediatelayer 500 and the cladding layer 600 together may form a coating surface450 on the substrate part 400 that is at least 0.1 μm thick.

Turning to FIGS. 9 and 10, once the intermediate layer 500 and thecladding layer 600 have been formed on the substrate part 400, thefinishing step 350 may be performed to obtain final dimensions thatcorrespond to a finished metal face seal. As shown in FIG. 9, thefinishing step 350 may comprise a surface finishing process which mayinclude one or more of grinding, polishing, milling, machining, or othersuitable process to remove material 710 from a top surface 605 of thecladding layer 600 to obtain final dimensions of a finished metal faceseal. In select aspects, the finishing step 350 may comprise a heattreatment process, which may be performed before or after the surfacefinishing process, to enhance material properties of the substrate part400. The heat treatment process may include thermal hot flattening wherethe substrate part 400 is compressed in a thermally controlledenvironment to relieve product stresses. In select aspects, the claddinglayer 600 is finished to a cladding layer thickness of between 0.7 mmand 1.0 mm. The cladding layer 600 may have a Rockwell hardness ofbetween HRC 60 and 65. In select aspects, the Rockwell hardness of thecladding layer 600 may be between 62 and 64. In select aspects, the topsurface 605 of the cladding layer 600 is free of cracks.

As shown in FIG. 10, in select aspects, the finishing step 350 mayinclude grinding, polishing, milling, machining, and/or other suitablemachining process to remove material 720 from the outer diameter surface410 of the substrate part 400, the intermediate layer 500, and/or thecladding layer 600 to obtain final dimensions that correspond to afinished mechanical face seal. In select aspects, the finishing step 350may include grinding, polishing, milling, machining, and/or othersuitable process to remove material 730 from the inner diameter surface420 of the substrate part 400, the intermediate layer 500, and/or thecladding layer 600 to obtain final dimensions that correspond to afinished mechanical face seal.

Referring to FIGS. 11 and 12, the disclosure provides a method offorming mechanical face seals using a thermal spray coating process. Thethermal spray coating process may enable use of less expensivesubstrates, less coating materials, increase performance, and reducemanufacturing complexity and cost in comparison with conventionaltechniques and/or seal rings made of expensive exotic wear resistantsubstrates such as titanium or zirconium. The method may further improvelubrication properties of the finished mechanical face seals incomparison with those produced using conventional techniques. The methodof thermal spray coating 1000 may include an obtaining step 1010.Similar to the obtaining step 310 described above with respect to themethod of laser cladding 300, the obtaining step 1010 may includeobtaining or forming a substrate part 1100, which may be wrought or castusing an SAE 52100 alloy steel, SAE 1020 alloy steel, SAE 1040 alloysteel, ductile iron, or grey cast iron. Other materials are contemplatedas well and will be appreciated by those skilled in the art in view ofthe present disclosure. The substrate part 1100 may be wrought or castto have roughly a geometry of a finished mechanical face seal. Inaddition, or as an alternative, the substrate part 1100 may be formed bya powder metallurgy or other suitable process. In select aspects, theobtaining step 1010 may comprise refurbishing, repairing, or salvaging apreviously used or damaged substrate part in order to obtain a substratepart 1100. In select aspects, the substrate part 1100 may include arecessed or sloped surface adjacent to the planar surface 1140 forforming a final seal ring which be used in a spring-loaded metal faceseal arrangement (such as the one shown in FIG. 5, for example).

After the substrate part 1100 has been obtained, the substrate part 1100may undergo a rough surface treatment step 1020. The rough surfacetreatment step 1020 may include roughening of at least one surface toform an adhesion surface where the thermal spray coating may be appliedonto. In select aspects, the rough surface treatment step 1020 may beapplied to a planar surface 1140 of the substrate part 1100 to formpores, peaks, and valleys on the planar surface 1140, which may beconsidered as the adhesion surface. The rough surface treatment step1020 may include one or more of rough machining and grit blasting of thesubstrate part 1100 to form the adhesion surface. Other processes andmethods for roughing a surface of the substrate part 1100 in order toform pores, peaks, and valleys are of course contemplated. In selectaspects, where the substrate part 1100 includes the recessed or slopedsurface adjacent to the planar surface 1140, the recessed or slopedsurface may also undergo the rough surface treatment step 1020.

A spraying step 1030 may be performed after the obtaining step 1010, orafter the rough surface treatment step 1020. During the spraying step1030, a spray coating material 1250 may be supplied to a top layer 1141of the substrate part 1100, which may be a top surface or portion of theplanar surface 1140. The spray coating material 1250 may be in the formof a powder or a wire feedstock. The spray coating material 1250 may bemade of a Fe-based alloy, a Ni-based alloy, a Co-based alloy, acarbide-based material, and/or a ceramic material. The carbide-basedmaterials may include tungsten and/or chromium. The ceramic materialsmay include Al-oxides, Co-oxides, and/or Ti-oxides. In select aspects,the spray coating material 1250 may include one or more of M2, M4, andT15 alloys. In select aspects, the spray coating material 1250 mayinclude a depressed-eutectic alloy, which may include silicon, boron,carbon, and/or phosphorous. In select aspects, the coating material 1250may consist of a Ni-based alloy having a chemical composition of 16-17%chromium, 3.3% boron, 3.8% silicon, 0.8% to 1.0% carbon, and a balanceof nickel. In select aspects, the coating material 1250 may consist of aFe-based alloy having a chemical composition of 0.78% to 1.05% carbon,0.15% to 0.40% manganese, 0.20% to 0.45% silicon, 2.0% to 4.5% chromium,4.5% to 5.5% molybdenum, 5.5% to 6.75% tungsten, 1.75% to 2.20%vanadium, up to 0.3% nickel, up to 0.25% copper, up to 0.03% phosphorus,up to 0.03% sulfur, and a balance of iron. In select aspects, thecoating material 1250 may consist of a Co-based alloy having acomposition of 26.5% to 33% chromium, 0.8% to 2.7% carbon, 3.5% to 20%tungsten, 0.8% to 1.2% silicon, up to 3% iron, up to 1.5% molybdenum, upto 1% manganese, and a balance of cobalt.

The spray coating material 1250 may be heated to a predeterminedtemperature and sprayed onto the top layer 1141. In select aspects, thepredetermined temperature may be at or above a melting point of thespray coating material 1250. As the spray coating material 1250 issupplied to the top layer 1141 of the substrate part 1100, the spraycoating material 1250 may be at least partially deposited within thepores and/or within the valleys of the top layer 1141. As the spraycoating material 1250 is supplied to the top layer 1141 of the substratepart 1100, the spray coating material 1250 may solidify onto and abovethe top layer 1141 of the substrate part 1100 to form a thermal spraycoating layer 1300, as shown in FIG. 13. In one aspect, the sprayingstep 1030 may be performed to form the thermal spray coating layer 1300without or substantially without any cracks. In select aspects, thethermal spray coating layer 1300 may form a micro-porous structure, andthe micro-porous structure may promote retention of lubrication duringuse of the finished mechanical face seal to further improve wear life.In select aspects, where the substrate part 1100 includes the recessedor sloped surface adjacent to the planar surface 1140, the spray coatingmaterial 1250 may be sprayed onto the recessed or sloped surface duringthe spraying step 1030. In select aspects, the spray coating material1250 may be prevented from being applied onto the recess or slopedsurface to preserve a prescribed gap distance between two opposing sealrings, when finished and assembled.

A finishing step 1040 may be performed on the substrate part 1100 toachieve final dimensions required by a particular mechanical face seal.The finishing step 1040 may be performed on any surface of the substratepart 1100. In one aspect, the finishing step 1040 may include a surfacefinishing process performed on the thermal spray coating layer 1300above the planar surface 1140. The finishing step 1040 may include oneor more of grinding, polishing, milling, machining, or other suitableprocess to finish one or more surfaces of the substrate part 1100. Inselect aspects, where the substrate part 1100 includes the recessed orsloped surface adjacent to the planar surface 1140, the finishing step1040 may also be performed on the recessed or sloped surface.

Referring to FIG. 13, the substrate part 1100 may include at least anouter diameter surface 1110 and an inner diameter surface 1120 extendingalong a common central axis 1130. The substrate part 1100 may includethe planar surface 1140 extending between the outer diameter surface1110 and the inner diameter surface 1120. When processed and finished,the planar surface 1140 of the substrate part 1100 may form a surface ofa mechanical seal ring for contact at an interface between twomechanical face seals. As discussed above with respect to the obtainingstep 1010, the substrate part 1100 may be wrought or cast using an SAE52100 alloy steel, SAE 1020 alloy steel, SAE 1040 alloy steel, ductileiron, or grey cast iron. Other materials are contemplated as well. Thesubstrate part 1100 may be wrought or cast to have roughly a geometry ofa finished mechanical face seal. In select aspects, the obtaining step1010 may comprise refurbishing, repairing, or salvaging a previouslyused or damaged substrate part in order to obtain the substrate part1100.

During the obtaining step 1010, the substrate part 1100 may be formedinto a ring-shaped element. In select aspects, the substrate part 1100may be made of SAE 52100 alloy steel, which may have a chemicalcomposition of 1.3% to 1.6% chromium, 0.93% to 1.1% carbon, 0.25% to0.45% manganese, 0.15% to 0.35% silicon, up to 0.025% sulfur, up to0.025% phosphorous, and a balance of iron. In select aspects, thesubstrate part 1100 may be made of SAE 1020 alloy steel, which may havea chemical composition of 0.18% to 0.23% carbon, 0.3% to 0.6% manganese,up to 0.04% phosphorus, up to 0.05% sulfur, and a balance of iron. Inselect aspects, the substrate part 1100 may be made of SAE 1040 alloysteel, which may have a chemical composition of 0.37% to 0.44% carbon,0.6% to 0.9% manganese, up to 0.04% phosphorus, up to 0.05% sulfur, anda balance of iron. In select aspects, the substrate part 1100 may bemade of ductile iron, which may have a chemical composition of 3.0% to3.9% carbon, 1.7% to 2.9% silicon, 0.1% to 0.6% manganese, 0.02% to0.06% magnesium, 0.005% to 0.04% phosphorus, up to 0.04% sulfur, up to0.4% copper, and a balance of iron. In select aspects, the cast ironsubstrate may be made of grey cast iron, which may have a chemicalcomposition of 2.5% to 4.0% carbon, 1% to 3% silicon, and a balance ofiron.

In one aspect, the rough surface treatment step 1020 may be performed toprovide an adhesion surface with pores, peaks, and valleys to promotebonding of the spray coating material 1250 onto the substrate part 1100.In select aspects, the rough surface treatment step 1020 may include oneor more of rough machining and grit blasting of the planar surface 1140of the substrate part 1100, which may be considered as the adhesionsurface. Alternatively, the substrate part 1100 may be obtained orformed with an inherent rough surface such that the rough surfacetreatment step 1020 is not needed or is minimized.

The spraying step 1030 may be performed to apply the spray coatingmaterial 1250 onto the substrate part 1100, and may include one or moreof a HVOF spray, TWA spray, high velocity air fuel (HVAF) spray, plasmaarc spray, and kinetic/cold spray. In one aspect, the spray coatingmaterial 1250 may be heated to form molten particles prior to beingsprayed and deposited onto a surface of the substrate part 1100, asdiscussed with respect to the spraying step 1030 described above. Themolten particles may enhance the spray coating material's 1250 abilityto grab onto the adhesion surface formed during the rough surfacetreatment step 1020.

The spraying step 1030 may include supplying and spraying the spraycoating material 1250 via a sprayer 1200. In select aspects, the sprayer1200 may include a spray head 1210 for aiming and directing the spraycoating material 1250 toward a surface of the substrate part 1100, suchas the planar surface 1140 of the substrate part 1100. In selectaspects, the sprayer 1200 may include a heating element 1220, which mayheat up the spray coating material 1250 prior to being sprayed onto thesubstrate part 1100. Because the substrate part 1100 itself does notneed to be heated, use of the method of thermal spray coating 1000 mayhave a further benefit of reducing distortion of the substrate part 1100and therefore reduced distortion of the finished mechanical seal,particularly compared with other processes that require a separate heattreatment step.

The sprayer 1200 may be attached to a robotic arm or actuator 1230, andthe robotic arm or actuator 1230 may be operable to move the sprayer1200 in a radial direction relative to the substrate part 1100. Forexample, during the spraying step 1030, the sprayer 1200 may be fixed ata predetermined height above the substrate part 1100, and the roboticarm or actuator 1230 may be actuated to move the sprayer 1200 back andforth above the substrate part 1100 in the radial direction between alocation of the outer diameter surface 1110 and the inner diametersurface 1120 of the substrate part 1100. Additionally, while the sprayer1200 is being actuated back and forth above the substrate part 1100, thesubstrate part 1100 may also be rotated about the common central axis1130, thereby enabling the sprayer 1200 to apply an even coating of thespray coating material 1250 onto the substrate part 1100. In selectaspects, the substrate part 1100 may be rotated at a rate of severalhundred rotations per minute (RPM) to enable a uniform application ofthe spray coating material 1250 onto the planar surface 1140 of thesubstrate part 1100. For example, the substrate part 1100 may be rotatedat a rate of between 100 RPM and 300 RPM as the spray coating material1250 is applied onto the substrate part 1100 from the sprayer 1200.

Although one aspect of the spraying step 1030 is to apply the spraycoating material 1250 onto a pre-specified adhesion surface, such as theplanar surface 1140, a small amount of the spray coating material 1250may adhere to one or more of the outer diameter surface 1110 and theinner diameter surface 1120 of the substrate part 1100. The small amountof spray or “overspray” on the outer diameter surface 1110 and/or theinner diameter surface 1120 may provide a light protective coating thatcan be beneficial against corrosion of the substrate part 1100. Inselect aspects, where the additional corrosion protection is notrequired or desired, the outer diameter surface 1110 and/or the innerdiameter surface 1120 may be masked off prior to the spraying step 1030to prevent any overspray from adhering onto the outer diameter surface1110 and/or the inner diameter surface 1120. In select aspects, theoverspray may be applied onto only the outer diameter surface 1110 ofthe substrate part 1100 for corrosion protection.

Turning to FIG. 14, once the thermal spray coating layer 1300 has beenformed on the substrate part 1100, the finishing step 1040 may beperformed to obtain final dimensions that correspond to a finishmechanical face seal. As shown in FIG. 14, the finishing step 1040 maycomprise a surface finishing process which may include one or more ofgrinding, polishing, milling, machining, or other suitable process toremove material 1410 from a top surface 1305 of the thermal spraycoating layer 1300 to obtain final dimensions of a finished mechanicalface seal. The finishing step 1040 may remove material between 100microns and 200 microns in depth from the thermal spray coating layer1300 formed during spraying step 1030.

In select aspects, the thermal spray coating layer 1300 may be finishedto a thermal spray coating layer thickness of between 0.1 mm and 2.0 mm.In select aspects, the thermal spray coating layer thickness may beapproximately 0.7 mm, when selecting a relatively more wear resistantmaterial from the list of spray coating materials 1250 discussed above,and approximately 1.2 mm when selecting a relatively less wear resistantmaterial. In select aspects, the top surface 1305 of the thermal spraycoating layer 1300 is free of cracks and may include micro pores withdepths greater than those formed during the laser cladding process. Inselect aspects, the micro pores may define valleys with depths between0.25 microns and 1.0 microns. These large valleys may advantageouslyhold pockets of lubricant during operation and enhance cooling ofsliding surfaces of the mechanical seal.

INDUSTRIAL APPLICABILITY

The disclosure is applicable to bearing surfaces, and in particularmechanical face seals. Various aspects of the disclosure provide acost-effective substrate part that may be laser cladded and/or thermallyspray coated to achieve superior strength and resistance against harshenvironments. The substrate part 400 may be laser cladded and finishedto form mechanical face seals, as shown in FIGS. 7-10, or the substratepart 1100 may be provided with the thermal spray coating 1000 to formthe mechanical face seals, as shown in FIGS. 12-14. These mechanicalface seals may be used in heavy duty rotating applications, such asaxles, gearboxes, tracked vehicles, conveyer systems, etc. As shown inFIGS. 3 and 4, the mechanical face seals, when installed in a rotatingapplication, may include two identical metal seal rings 110, 112, 210,212 that are mounted face-to-face with one another in two separatehousings or retainers. One of the two metal seal rings 112, 210 remainsstatic in its respective retainer 102, 202, while the other of the twometal seal rings 110, 212 rotates with its counter face rotatingretainer 104, 204.

With reference to the method of laser cladding 300, the substrate part400 may be provided or formed in the obtaining step 310. As shown inFIG. 7, the substrate part 400 may be wrought or cast out of SAE 52100steel, SAE 1020 alloy steel, SAE 1040 alloy steel, ductile iron, or greycast iron. In select aspects, the substrate part 400 may be made of SAE52100 alloy steel, the SAE 52100 alloy steel having a chemicalcomposition of 1.3% to 1.6% chromium, 0.93% to 1.1% carbon, 0.25% to0.45% manganese, 0.15% to 0.35% silicon, up to 0.025% sulfur, up to0.025% phosphorous, and a balance of iron. In select aspects, thesubstrate part 400 may be made of SAE 1020 alloy steel, which may have achemical composition of 0.18% to 0.23% carbon, 0.3% to 0.6% manganese,up to 0.04% phosphorus, up to 0.05% sulfur, and a balance of iron. Inselect aspects, the substrate part 400 may be made of SAE 1040 alloysteel, which may have a chemical composition of 0.37% to 0.44% carbon,0.6% to 0.9% manganese, up to 0.04% phosphorus, up to 0.05% sulfur, anda balance of iron. In select aspects, the substrate part 400 may be madeof ductile iron, which may have a chemical composition of 3.0% to 3.9%carbon, 1.7% to 2.9% silicon, 0.1% to 0.6% manganese, 0.02% to 0.06%magnesium, 0.005% to 0.04% phosphorus, up to 0.04% sulfur, up to 0.4%copper, and a balance of iron. In select aspects, the cast ironsubstrate may be made of grey cast iron, the grey cast iron having achemical composition of 2.5% to 4.0% carbon, 1% to 3% silicon, and abalance of iron.

During the supplying step 340, the coating material 950 supplied to thetop layer 441 of the substrate part 400 may be made of Fe-based alloys,Ni-based alloys, or Co-based alloys. In select aspects, the coatingmaterial 950 may include Durmat® 60A, M2 tool steel, Stellite® 1,Stellite® 6, or other suitable material. In select aspects, the coatingmaterial 950 may consist of a Ni-based alloy having a chemicalcomposition of 16-17% chromium, 3.3% boron, 3.8% silicon, 0.8% to 1.0%carbon, and a balance of nickel. In select aspects, the coating material950 may consist of a Fe-based alloy having a chemical composition of0.78% to 1.05% carbon, 0.15% to 0.40% manganese, 0.20% to 0.45% silicon,2.0% to 4.5% chromium, 4.5% to 5.5% molybdenum, 5.5% to 6.75% tungsten,1.75% to 2.20% vanadium, up to 0.3% nickel, up to 0.25% copper, up to0.03% phosphorus, up to 0.03% sulfur, and a balance of iron. In selectaspects, the coating material 950 may consist of a Co-based alloy havinga composition of 26.5% to 33% chromium, 0.8% to 2.7% carbon, 3.5% to 20%tungsten, 0.8% to 1.2% silicon, up to 3% iron, up to 1.5% molybdenum, upto 1% manganese, and a balance of cobalt.

The substrate part 400 may be preheated in the preheating step 320. Thesubstrate part 400 may be exposed to the laser 800 during the exposingstep 330, and coating material 950 may be supplied to the top layer 441of the substrate part 400 to form the intermediate layer 500 and/or thecladding layer 600, as shown in FIG. 8. The finishing step 350 may beperformed to finish the top surface 605 of the cladding layer 600, theouter diameter surface 410 of the substrate part 400, and/or the innerdiameter surface 420 of the substrate part 400 during a surfacefinishing process, as shown in FIGS. 9 and 10. The finishing step 350may include a heat treatment process where the substrate part 400 iscompressed in a thermally controlled environment to relieve productstresses. In select aspects, the top surface 605 of the cladding layer600 is free of cracks. Once finished, the substrate part 400 forms acompleted mechanical face seal, which may be used in rotatingapplications such as axles, gearboxes, tracked vehicles, conveyersystems, etc. The low cost substrate part 400 in addition to thecladding layer 600 enables mechanical faces seals to be produced in amore cost effective manner while still providing the necessary strengthand durability to withstand harsh environmental operating conditions.

With reference to the method of thermal spray coating 1000, thesubstrate part 1100 may be provided or formed in the obtaining step1010. As shown in FIG. 12, the substrate part 1100 may be wrought orcast out of SAE 52100 alloy steel, which may have a chemical compositionof 1.3% to 1.6% chromium, 0.93% to 1.1% carbon, 0.25% to 0.45%manganese, 0.15% to 0.35% silicon, up to 0.025% sulfur, up to 0.025%phosphorous, and a balance of iron. In select aspects, the substratepart 1100 may be made of SAE 1020 alloy steel, which may have a chemicalcomposition of 0.18% to 0.23% carbon, 0.3% to 0.6% manganese, up to0.04% phosphorus, up to 0.05% sulfur, and a balance of iron. In selectaspects, the substrate part 1100 may be made of SAE 1040 alloy steel,which may have a chemical composition of 0.37% to 0.44% carbon, 0.6% to0.9% manganese, up to 0.04% phosphorus, up to 0.05% sulfur, and abalance of iron. In select aspects, the substrate part 1100 may be madeof ductile iron, which may have a chemical composition of 3.0% to 3.9%carbon, 1.7% to 2.9% silicon, 0.1% to 0.6% manganese, 0.02% to 0.06%magnesium, 0.005% to 0.04% phosphorus, up to 0.04% sulfur, up to 0.4%copper, and a balance of iron. In select aspects, the cast ironsubstrate may be made of grey cast iron, which may have a chemicalcomposition of 2.5% to 4.0% carbon, 1% to 3% silicon, and a balance ofiron.

The spray coating material 1250 to be applied to the substrate part 1100may be in the form of a powder or a wire feedstock. The spray coatingmaterial 1250 may be made of Fe-based alloys, Ni-based alloys, Co-basedalloys, carbide-based materials, and/or ceramic materials. Thecarbide-based materials may include tungsten and/or chromium. Theceramic materials may include Al-oxides, Co-oxides, and/or Ti-oxides. Inselect aspects, the spray coating material 1250 may include one or moreof M2, M4, and T15 alloys. In select aspects, the spray coating material1250 may include a depressed-eutectic alloy, which may include silicon,boron, carbon, and/or phosphorous. In select aspects, the coatingmaterial 1250 may consist of a Ni-based alloy having a chemicalcomposition of 16-17% chromium, 3.3% boron, 3.8% silicon, 0.8% to 1.0%carbon, and a balance of nickel. In select aspects, the coating material1250 may consist of a Fe-based alloy having a chemical composition of0.78% to 1.05% carbon, 0.15% to 0.40% manganese, 0.20% to 0.45% silicon,2.0% to 4.5% chromium, 4.5% to 5.5% molybdenum, 5.5% to 6.75% tungsten,1.75% to 2.20% vanadium, up to 0.3% nickel, up to 0.25% copper, up to0.03% phosphorus, up to 0.03% sulfur, and a balance of iron. In selectaspects, the coating material 1250 may consist of a Co-based alloyhaving a composition of 26.5% to 33% chromium, 0.8% to 2.7% carbon, 3.5%to 20% tungsten, 0.8% to 1.2% silicon, up to 3% iron, up to 1.5%molybdenum, up to 1% manganese, and a balance of cobalt.

During the rough surface treatment step 1020, the planar surface 1140 ofthe substrate part 1100 may be treated to form pores, peaks, and valleyson the planar surface 1140. The rough surface treatment step 1020 mayinclude one or more of rough machining and grit blasting of thesubstrate part 1100, which may include rough machining and/or gritblasting of the planar surface 1140. In select aspects, the substratepart 1100 may include a recessed or sloped surface adjacent to theplanar surface 1140, which may be used to form a seal ring to be used ina spring-loaded metal face seal arrangement. The recessed or slopedsurface adjacent to the planar surface 1140 may also undergo the roughsurface treatment step 1020.

During the spraying step 1030, the spray coating material 1250 may besprayed onto the substrate part 1100 via the sprayer 1200, as shown inFIG. 12. The sprayer 1200 may include the spray head 1210 for aiming anddirecting the spray coating material 1250 onto a surface of thesubstrate part 1100, such as the planar surface 1140. In select aspects,where the substrate part 1100 includes the recessed or sloped surfaceadjacent to the planar surface 1140, the spray coating material 1250 maybe sprayed onto the recessed or sloped surface during the spraying step1030. In select aspects, the spray coating material 1250 may beprevented from being applied onto the recess or sloped surface topreserve a prescribed gap distance between two opposing seal rings, whenfinished and assembled.

In select aspects, the sprayer 1200 may be attached to a robotic arm oractuator 1230, and the sprayer 1200 may be actuated in the radialdirection, relative to the substrate part 1100, in order to reach andprovide coverage of the spray coating material 1250 across an entiresurface of the substrate part 1100, such as the planar surface 1140.Additionally, or alternatively, the substrate part 1100 may be rotatedabout the common central axis 1130 in order to enable a uniformapplication of the spray coating material 1250 onto the planar surface1140 of the substrate part 1100. In select aspects, the substrate part1100 may be rotated at a rate of between 100 RPM and 300 RPM as thespray coating material 1250 is sprayed onto the substrate part 1100 fromthe sprayer 1200, and the sprayer 1200 may be actuated to move back andforth above the substrate part 1100 in the radial direction between alocation of the outer diameter surface 1110 and the inner diametersurface 1120 of the substrate part 1100.

The sprayer 1200 may include the heating element 1220, which may be usedto heat the spray coating material 1250 to form molten particles priorto being sprayed and deposited onto a surface of the substrate part1100. These molten particles may enhance the spray coating material's1250 ability to grab onto the adhesion surface formed during the roughsurface treatment step 1020. A thickness of between 0.1 mm and 2.0 mm ofthe spray coating material 1250 may be deposited or applied to thesubstrate part 1100 to form the thermal spray coating layer 1300 abovethe planar surface 1140, as shown in FIG. 13. The thermal spray coatinglayer 1300 may define micro pores with depths of between 0.25 micronsand 1.0 microns that may advantageously hold pockets of lubricant duringoperation and enhance cooling of sliding surfaces of the mechanical sealduring use.

During the finishing step 1040, a surface finishing process may beperformed on the thermal spray coating layer 1300 above the planarsurface 1140, as shown in FIG. 14. The finishing step 1040 may includeone or more of grinding, polishing, milling, machining, or othersuitable process to finish one or more surfaces of the substrate part1100. In select aspects, a depth of between 100 microns and 200 micronsof material may be removed from the thermal spray coating layer 1300. Inselect aspects, where the substrate part 1100 includes the recessed orsloped surface adjacent to the planar surface 1140, the finishing step1040 may also be performed on the recessed or sloped surface.

Once finished, the substrate part 1100 forms a completed mechanical faceseal, which may be used in rotating applications such as axles,gearboxes, tracked vehicles, conveyer systems, etc. The low costsubstrate part 1100 in addition to the thermal spray coating layer 1300enable mechanical faces seals to be produced in a more time and costeffective manner while still providing the necessary strength anddurability to withstand harsh environmental operating conditions. Inparticular, the method of thermal spray coating 1000 may require lesscoating material to be applied to the substrate part 1100, compared withother methods in the related art, thereby reducing the overall materialcost and the amount of time required for the application of the spraycoating material 1250 onto the substrate part 1100. Furthermore, sinceless material may be applied onto the substrate part 1100, a reductionin time required to obtain final dimensions during the finishing step1040 may also be achieved.

It will be appreciated that the foregoing description provides examplesof the disclosed system and technique. However, it is contemplated thatother implementations of the disclosure may differ in detail from theforegoing examples. All references to the disclosure or examples thereofare intended to reference the particular example being discussed at thatpoint and are not intended to imply any limitation as to the scope ofthe disclosure more generally. All language of distinction anddisparagement with respect to certain features is intended to indicate alack of preference for those features, but not to exclude such from thescope of the disclosure entirely unless otherwise indicated.

Recitation of ranges of values herein are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein, and eachseparate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context.

We claim:
 1. A method of producing a mechanical face seal, the methodcomprising: forming a cast or wrought substrate part having an innerdiameter, an outer diameter, and a planar surface extending between theinner diameter and the outer diameter; roughing the planar surface ofthe substrate part; and applying a coating material onto the planarsurface to form a thermal coating layer on the substrate part, thecoating material comprising at least one of a Fe-based alloy, a Ni-basedalloy, a Co-based alloy, a carbide-based material, and a ceramicmaterial.
 2. The method of claim 1, further comprising finishing thethermal coating layer formed on the substrate part, wherein thefinishing includes removing material from the thermal coating layer toyield a thermal coating layer thickness of between 0.1 mm and 2.0 mm. 3.The method of claim 1, wherein the finishing includes removing a depthof between 100 microns and 200 microns of material from the thermalcoating layer.
 4. The method of claim 1, wherein the roughing formspores, peaks, and valleys on the planar surface of the substrate part.5. The method of claim 1, wherein the roughing forms pores, peaks, andvalleys on the planar surface of the substrate part, and wherein theapplying includes heating the coating material to form molten particlesto be applied onto the planar surface and into the valleys on the planarsurface of the substrate part.
 6. The method of claim 1, wherein theapplying includes heating the coating material to form molten particlesto be applied onto the planar surface of the substrate part.
 7. Themethod of claim 1, wherein the applying includes spraying the coatingmaterial onto the planar surface via a sprayer, and moving the sprayerback and forth above the substrate part in a radial direction between alocation of the outer diameter and the inner diameter of the substratepart.
 8. The method of claim 7, wherein the applying includes rotatingthe substrate part at a rate of between 100 RPM and 300 RPM while thecoating material is applied onto the planar surface of the substratepart.
 9. The method of claim 1, wherein the thermal coating layer formsa coating surface on the substrate part that is free of cracks.
 10. Themethod of claim 1, wherein the substrate part is made of SAE 52100 alloysteel, SAE 1020 alloy steel, SAE 1040 alloy steel, ductile iron, or greycast iron.
 11. The method of claim 1, wherein the Fe-based alloyconsists of 0.78% to 1.05% carbon, 0.15% to 0.40% manganese, 0.20% to0.45% silicon, 2.0% to 4.5% chromium, 4.5% to 5.5% molybdenum, 5.5% to6.75% tungsten, 1.75% to 2.20% vanadium, up to 0.3% nickel, up to 0.25%copper, up to 0.03% phosphorus, up to 0.03% sulfur, and a balance ofiron, wherein the Ni-based alloy consists of 16-17% chromium, 3.3%boron, 3.8% silicon, 0.8% to 1.0% carbon, and a balance of nickel, andwherein the Co-based alloy consists of 26.5% to 33% chromium, 0.8% to2.7% carbon, 3.5% to 20% tungsten, 0.8% to 1.2% silicon, up to 3% iron,up to 1.5% molybdenum, up to 1% manganese, and a balance of cobalt. 12.A mechanical face seal formed by the method of claim
 1. 13. A method ofproducing a mechanical face seal, the method comprising: forming a castor wrought substrate part having an inner diameter, an outer diameter,and a planar surface extending between the inner diameter and the outerdiameter; roughing the planar surface of the substrate part to formpores, peaks, and valleys on the planar surface of the substrate part;and spraying a coating material that has been heated to moltenparticles, via a heating element and a spray head, onto the planarsurface to form a thermal spray coating layer on the substrate part, thecoating material comprising at least one of a Fe-based alloy, a Ni-basedalloy, a Co-based alloy, a carbide-based material, and a ceramicmaterial.
 14. The method of claim 13, further comprising finishing thethermal spray coating layer formed on the substrate part, wherein thefinishing includes removing material from the thermal spray coatinglayer to yield a thermal spray coating layer thickness of between 0.1 mmand 2.0 mm.
 15. The method of claim 13, wherein the finishing includesremoving a depth of between 100 microns and 200 microns of material fromthe thermal spray coating layer.
 16. The method of claim 13, wherein themolten particles are applied onto the planar surface and into thevalleys on the planar surface of the substrate part.
 17. The method ofclaim 13, wherein the spraying includes moving the spray head back andforth above the substrate part in a radial direction between a locationof the outer diameter and the inner diameter of the substrate part. 18.The method of claim 17, wherein the spraying includes rotating thesubstrate part at a rate of between 100 RPM and 300 RPM while the spraycoating material is applied onto the planar surface of the substratepart.
 19. The method of claim 13, wherein the Fe-based alloy consists of0.78% to 1.05% carbon, 0.15% to 0.40% manganese, 0.20% to 0.45% silicon,2.0% to 4.5% chromium, 4.5% to 5.5% molybdenum, 5.5% to 6.75% tungsten,1.75% to 2.20% vanadium, up to 0.3% nickel, up to 0.25% copper, up to0.03% phosphorus, up to 0.03% sulfur, and a balance of iron, wherein theNi-based alloy consists of 16-17% chromium, 3.3% boron, 3.8% silicon,0.8% to 1.0% carbon, and a balance of nickel, and wherein the Co-basedalloy consists of 26.5% to 33% chromium, 0.8% to 2.7% carbon, 3.5% to20% tungsten, 0.8% to 1.2% silicon, up to 3% iron, up to 1.5%molybdenum, up to 1% manganese, and a balance of cobalt.
 20. A method ofproducing a mechanical face seal, the method comprising: forming a castor wrought substrate part, the substrate part having an inner diameter,an outer diameter, and a planar surface extending between the innerdiameter and the outer diameter; roughing the planar surface of thesubstrate part; and spraying a coating material via a sprayer onto theplanar surface to form a thermal spray coating layer on the substratepart, the coating material comprising at least one of a Fe-based alloy,a Ni-based alloy, a Co-based alloy, a carbide-based material, and aceramic material, wherein the Fe-based alloy consists of 0.78% to 1.05%carbon, 0.15% to 0.40% manganese, 0.20% to 0.45% silicon, 2.0% to 4.5%chromium, 4.5% to 5.5% molybdenum, 5.5% to 6.75% tungsten, 1.75% to2.20% vanadium, up to 0.3% nickel, up to 0.25% copper, up to 0.03%phosphorus, up to 0.03% sulfur, and a balance of iron, wherein theNi-based alloy consists of 16-17% chromium, 3.3% boron, 3.8% silicon,0.8% to 1.0% carbon, and a balance of nickel, wherein the Co-based alloyconsists of 26.5% to 33% chromium, 0.8% to 2.7% carbon, 3.5% to 20%tungsten, 0.8% to 1.2% silicon, up to 3% iron, up to 1.5% molybdenum, upto 1% manganese, and a balance of cobalt, wherein the carbide-basedmaterial includes at least one of tungsten and chromium, and wherein theceramic material includes at least one of aluminum oxides, cobaltoxides, and titanium oxides.